Pitching herself as a candidate for Prime Minister at the head of an unlikely Lib Dem majority government, Ms Swinson said she would “revoke Article 50 on day one” and cancel Brexit.
While a so-called People’s Vote on whether to stay in the EU remains Lib Dem policy, there was no mention of it in a speech that saw Ms Swinson bill the coming election as “the fight of our lives for the heart and soul of Britain” against populist politics.
“The next few weeks are about deciding what kind of country we are, and who we want to be,” she said. “Whether we tackle our biggest challenges with our closest allies, or on our own; whether we welcome those who want to build a better life in our country, or shut the door on them; whether we ensure every single child can go on and fulfil their dreams.”
The speech contained no detailed policy announcements, but Ms Swinson did pledge to make national wellbeing a part of the budget-writing process, and adopt a Scottish-style public health approach to tackling knife crime.
The Lib Dem leader got a standing ovation from cheering party members gathered in Bournemouth as she told them: “Today I am standing here as your candidate for Prime Minister”.
“The first task is clear,” she went on. “We must stop Brexit.
“And we are crystal clear: a Liberal Democrat majority government will revoke Article 50 on day one.
“Because there is no Brexit that will be good for our country.”
Singling out what she claimed was the divisive populism of both Boris Johnson and Jeremy Corbyn, Ms Swinson said the country should have a “better choice than an entitled Etonian or a 1970s socialist”.
She made light of the Prime Minister’s complicated personal life, joking that “commitment has never been Boris Johnson’s strong suit”, and told delegates: “This Brexiteer Government wants to pay for their ideology with other people’s jobs”.
Ms Swinson compared the forces behind the Brexit vote to the push for Scottish independence, claiming they were both driven by “hate, fear and division”.
“For those of us who had lived through the 2014 independence referendum in Scotland, it all felt too familiar,” Ms Swinson said.
“I am Scottish. I am British. I am European.
“Scottish nationalism and English nationalism would both have me choose. But there is no contradiction.
“I am a proud Scot. I love our United Kingdom, and I feel stronger as part of the European family.”
Arguing that “the social contract is broken”, Ms Swinson said the Lib Dems would “fundamentally rethink the purpose of our economy” by basing policy and spending decisions on their impact on wellbeing - although Labour, the SNP and the Conservatives have all previously embraced the same principle.
Data already collected from the public on their satisfaction with life, and their levels of anxiety and happiness, would be used to evaluate government decisions.
Ms Swinson also dedicated a large portion of her speech to the need for greater action to tackle the climate crisis, and pledged to recreate a publicly-owned Green Investment Bank following the privatisation of the Edinburgh-based financial institution.
The Lib Dem leader became emotional as she told party members that her father, who died last year, had a “huge influence” on her life.
“He encouraged me to believe that we can change things for the better.
“He encouraged me to challenge the way things are.
“And above all, he taught me always to keep learning, to be curious, to ask questions.
“Actually, that’s what any good liberal does.”
She concluded: “Only a Liberal Democrat government can deliver the fair, inclusive and open future that we deserve.
“At the next general election, voters will choose the kind of country we want to be: insular, closed and selfish; or collaborative, open and generous.
“We can defeat nationalism and populism. We can change our politics, stop Brexit and win a brighter future.”